Micromixer

ABSTRACT

The inventive micromixer for mixing liquid, viscous or gaseous phases has a housing bottom part ( 2 ) and a housing top part ( 3 ) which lie closely against each other via connecting surfaces ( 6, 7 ). Two delivery channels ( 1   a   , 1   b ) and an outlet channel ( 5 ) open out into the dividing surface between the two connecting surface ( 6, 7 ). Channel grooves ( 9, 10 ) which cross each other several times are formed in one connecting surfaces ( 6 ) and provide a mixing section for the phases being mixed.

The invention relates to a micromixer for mixing at least two liquid,viscous or gaseous phases, having one inlet passage for each of thephases, a mixing section, in which the phase flows are crossed anddivided one or more times, and an outlet passage for the mixture.

Various embodiments of devices for mixing liquid, viscous or gaseousphases are known. The operating principle of these mixers consists individing and crossing the two or more phase flows which are to be mixedwith one another a number of times, so that an intensively mixed flow ofsubstance is formed at the end of the mixing section. To mix smallquantities it is known, for example, to form the mixing section in athin tube which contains mixing bodies which guide the two phases whichare to be mixed in passages which cross one another. However, suchtubular mixing sections are less suitable if it is necessary to mixparticularly small quantities and, for example, exact temperaturecontrol is required.

Therefore, the object of the invention is to design a micromixer of thegeneric type described in the introduction in such a way that, withlittle manufacturing outlay, it is possible to construct a mixingsection which has a very small receiving volume and allows exact anduniform temperature control in all areas. Moreover, the micromixer is tobe easy to clean and is to offer the option of using a very wide rangeof materials, so that it can be adapted to a very wide range of possibleapplications.

According to the invention, this object is achieved by the fact that ahousing bottom part and a housing top part bear against one another in asealed manner on connecting surfaces which face towards one another,that the inlet passages and the outlet passage open out into the partingface formed by the connecting surfaces, and that passage grooves, whichform the mixing section, are recessed in at least one of the twoconnecting surfaces.

Since the mixing section comprises exclusively those surfaces of thehousing parts which face towards one another and the passage grooveswhich are recessed therein, there is no need to provide separate mixingbodies. The passage grooves which are recessed in at least one of thetwo connecting surfaces can be made in any desired surface structure,cross-sectional design and profile adapted to the particularapplication, using precision-machining processes. Since the machiningtakes place only in the immediate vicinity of the surface, themanufacturing outlay required for this purpose is relatively low.

The simple, substantially plate-like structure of the two housing partsand, if appropriate, further intermediate housing plates which arearranged between these parts and each have a connecting surface on bothsides makes it possible to use a very wide range of materials, theselection of materials as far as possible depending only on therequirements of the substances to be mixed, since manufacturingengineering considerations largely fade into the background.

The seal between the contact surfaces which bear against one another iseffected by means of compressive forces, specifically by theprecision-machined surfaces and/or seals, for example O-ring seals orflat gaskets, being pressed together. After the micromixer has beenopened, all the areas which have come into contact with the substancesto be mixed can be cleaned in a simple manner.

Since all the areas of the passages which cross one another in themixing section as well as any connection grooves are formed in a uniformmanner in the connecting surface, the heat transfer conditions in allthe passage sections are also entirely uniform. Therefore, completelyuniform temperature control can be established in all sections of thepassages in the micromixer simply by regulating the temperature of thehousing parts. The very small cross section of the channel groovesresults in a very high ratio of the passage surface areas to the passagevolume, allowing very satisfactory heat exchange to be achieved. Thisalso contributes to increasing the operating reliability and enablesexact temperature control.

Preferably, the passage grooves are recessed in only one of the twoconnecting surfaces which bear against one another. Alternatively,however, it is also possible to recess passage grooves in bothconnecting surfaces.

According to a preferred embodiment of the invention, the mixing sectioncomprises two passage grooves which run in the form of a wave and crossone another a number of times. This shape of groove is particularlysimple to manufacture and results in a substantially equal passage crosssection in all areas of the passage, so that there are also constantconditions of heat transfer to the housing parts in all areas. Intensivemixing is achieved in a very small space and with a comparatively shortpassage length.

Further advantageous configurations of the inventive idea form thesubject matter of further subclaims.

Exemplary embodiments of the invention are explained in more detailbelow and are illustrated in the drawing, in which:

FIG. 1 shows a three-dimensional, exploded view of a micromixercomprising a housing bottom part and a housing top part, with theconnecting screws omitted, FIG. 1a shows a particular embodiment of thehousing bottom part, in which the passage grooves adjoining the inletpassages 1 a and 1 b join one another in a V shape, the point of the Vfacing in the opposite direction to the passage grooves running in theform of a wave.

FIG. 2 shows a similar illustration to that of FIG. 1 of a modifiedembodiment of a micromixer.

The micromixer shown in FIGS. 1 and 1a is used to mix two liquid,viscous or gaseous phases which are supplied via two inlet passages 1 a,1 b which are only diagrammatically depicted. The micromixer has ahousing bottom part 2 and a housing top part 3 which, in the exemplaryembodiments illustrated, are designed as simple rectangular plates. Inthe assembled state, the housing bottom part is connected to the housingtop part by means of screws, which are not shown and extend throughdrilled holes 4.

An outlet passage 5, which removes the mixed phase, leads out of themicromixer.

In the assembled state, the housing bottom part 2 and the housing toppart 3 bear directly against one another in a sealed manner on mutuallyfacing connecting surfaces 6 and 7, respectively. A mixing section 8 isformed in the connection surface 6 of the housing bottom part betweenthe inlet passages 1 a, 1 b and the outlet passage 5. The mixing section8 comprises two sinusoidal passage grooves 9 and 10 which are recessedin the connecting surface 6, run in the form of a wave and cross oneanother a number of times to form the mixing section 8. As a result, inthe exemplary embodiments shown in FIG. 1 and FIG. 1a, the two phaseflows supplied through the inlet passages 1 a, 1 b cross one another andare divided a number of times and are thus intensively mixed with oneanother. In particular embodiments, the passage grooves shown in thehousing bottom part 2 and adjoining the inlet passages 1 a and 1 b maybe Y-shaped, T-shaped or V-shaped, the point of the V facing in theopposite direction to the passage grooves running in the form of a wave.One of these particular embodiments is shown in FIG. 1a. The inletpassages 1 a and 1 b and the outlet passage 5 open into the parting faceformed by abutment of the surfaces 6 and 7 and pass laterally throughthe parting face.

The two inlet passages 1 a, 1 b each open out at one end of the two wavypassage grooves 9 and 10.

The exemplary embodiment shown in FIG. 2 differs from the exemplaryembodiment shown in FIG. 1 essentially through the fact that the twoinlet passages 1 a, 1 b are each connected to both ends of one of thewavy passage grooves 9 or 10, which form the mixing section, viaconnecting grooves 11, 12 or 13, 14, respectively. The outlet passage 5is connected in a central area of the passage grooves 9, 10 which crossone another. As a result, two mixing sections 8′ and 8″, which areconnected in parallel, are formed.

In the exemplary embodiment shown in FIG. 2, the housing bottom part 2′and the housing top part 3′ are designed in the form of a circular discand are provided at their outer edge with a chamfer 15 which enables thetwo housing parts 2′ and 3′ to be connected to one another by means of aflanged connecting element 20 which acts on the edge 21, for example aclamping ring.

The structure of the two micromixers illustrated by way of example canbe extended further by arranging one or more intermediate housing platesbetween the housing bottom part 2 or 2′ and the housing top part 3 or3′, which intermediate plates have a connecting surface on both sides.This makes it possible to construct a multistage mixer.

In addition to the mixing sections 8, 8′ and 8″ described, heatexchangers, pumps and/or other process engineering components can beformed by means of recesses in the connecting surfaces 6, 7 and, ifappropriate, the connecting surfaces of intermediate housing plates. Bymeans of further plates and/or other forms of passage, it is alsopossible to integrate dwell and precooling sections whose temperature isprecisely regulated in addition to heat exchangers and pumps.

In the exemplary embodiments illustrated, the housing parts are madefrom metal. As an alternative, it is also possible to use othermaterials, for example glass, plastics or ceramic. It is also possibleto provide a surface coating, for example by vapour deposition, so thatthose surfaces which come into contact with the phases to be mixed canbe selected in the particular material grade required.

What is claimed is:
 1. A micromixer for mixing at least two liquid,viscous or gaseous phases to produce a mixed product, the micromixercomprising: an inlet passage for each of the phases, a mixing section inwhich phase flows are crossed and divided a plurality of times, and anoutlet passage for the mixed phase product wherein; a) a housing bottompart (2, 2′) and a housing top part (3, 3′) directly bearing against oneanother in a sealed manner on abutting surfaces (6, 7) which facetowards one another and are detachably connected to one another by areleasable device exerting a compressive force thereagainst, b) theinlet passage (1 a, 1 b) for each phase and the outlet passage (5)opening into and passing laterally through a parting face formed byabutment of the connecting surfaces (6, 7), and c) a pair of sinusoidalpassage grooves (9, 10) forming the mixing section (8, 8′, 8″) recessedin at least one of the two connecting surfaces (6, 7), the grooves beingat the same level and intersecting one another a plurality of times. 2.A reusable micromixer according to claim 1, wherein the passage grooves(9, 10) are recessed in only one of the two connecting surfaces (6, 7)which bear against one another.
 3. A reusable micromixer according toclaim 1, wherein the two inlet passages (1 a, 1 b) are each connected toboth ends of one of the sinusoidal passage grooves (9 or 10) viaconnecting grooves (11, 12, 13, 14), and wherein the outlet passage (5)is connected to a central area of the sinusoidal passage grooves (9, 10)which intersect.
 4. A reusable micromixer according to claim 1, whereinthe housing top part (3′) and the housing bottom part (2′) are connectedto one another by a flanged connecting element which cooperates withperipheral edges of the parts (3′ and 2′).
 5. A reusable micromixeraccording to claim 1 wherein the housing bottom part (2, 2′) and thehousing top part (3, 3′) are made of metal.
 6. A reusable micromixeraccording to claim 1 wherein the housing bottom part and housing toppart are made of a material selected from the group consisting ofglasses, plastics or ceramics.
 7. A micromixer for mixing at least twoliquid, viscous or gaseous phases to produce a mixed product, themicromixer comprising: an inlet passage for each of the phases, a mixingsection in which phase flows are crossed and divided a plurality oftimes, and an outlet passage for the mixed phase product wherein; (a) ahousing bottom part (2, 2′), a housing top part (3, 3′) with anintermediate housing plate therebetween arranged in a sealed manner withabutting surfaces (6, 7) engaging the intermediate housing plate, theparts and plate being detachably connected to one another by areleasable device exerting a compressive force thereagainst, (b) theinlet passage (1 a, 1 b) for each phase and the outlet passage (5)opening into and passing laterally through a parting face formed byabutment of the connecting surfaces (6, 7) with the intermediate plate,and (c) a pair of sinusoidal passage grooves (9, 10) forming the mixingsection (8, 8′, 8″) recessed in at least one of the two connectingsurfaces (6, 7), the grooves being at the same level and intersectingone another a plurality of times.
 8. A micromixer for mixing at leasttwo liquid, viscous or gaseous phases to produce a mixed product, themicromixer comprising: an inlet passage for each of the phases, a mixingsection in which phase flows are crossed and divided a plurality oftimes, and an outlet passage for the mixed phase product wherein; (a) ahousing bottom part (2, 2′) and a housing top part (3, 3′) directlybearing against one another in a sealed manner on abutting surfaces (6,7) which face towards one another and are detachably connected to oneanother by a releasable device exerting a compressive forcethereagainst, (b) the inlet passage (1 a, 1 b) for each phase and theoutlet passage (5) opening into and passing laterally through a partingface formed by abutment of the connecting surfaces (6, 7), (c) a pair ofsinusoidal passage grooves (9, 10) forming the mixing section (8, 8′,8″) recessed in at least one of the two connecting surfaces (6, 7), thegrooves being at the same level and intersecting one another a pluralityof times, and (d) heat exchangers, pumps or process engineeringcomponents formed by recesses in the connecting surfaces.